Arrange the following complexes in increasing order of their magnetic moment

(A) $[NiCl_4]^{2-}$
(B) $[Fe(H_2O)_6]^{2+}$
(C) $[Cr(H_2O)_6]^{3+}$
(D) $[Co(C_2O_4)_3]{3-}$

Choose the correct answer from the options given below:

(D), (A), (C), (B)

The correct answer is Option (2) → (D), (A), (C), (B)

Calculation of spin-only magnetic moment ($μ = \sqrt{[n(n+2)]} BM$):

Increasing order of magnetic moment:

0 < 2.83 < 3.87 < 4.90

∴ (D) < (A) < (C) < (B)